Binary Search Tree

Learn the fundamentals of binary search trees and their insertion and search mechanics.

Binary Search Trees (BST) are used as in-memory data structures in databases to store ordered data and for some types of abstract data, such as priority queues and lookup tables.


Before diving in, let’s review a few important terms used for tree data structures:

  • Root: The root is the topmost node in a tree with no parent.

  • Leaves: Leaves are the bottommost nodes in the tree without children.

  • Key: A unique identifier representing a node in the tree.

  • Value: The data component associated with the key in the tree.


A BST is a sorted binary tree with the following properties:

  • Only one root node.

  • Every node has a key.

  • Every node in the BST has at most two children.

  • Every node splits the search space into left and right subtrees:

    • The left subtrees have node keys lesser than the parent node key.

    • The right subtrees have nodes greater than or equal to the parent node key.

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